问题
I'm trying to compute the number of rows with NA of the whole df as I'm looking to compute the % of rows with NA over the total number of rows of the df.
I have already have seen this post: Determine the number of rows with NAs but it just shows a specific range of columns.
回答1:
tl;dr: row wise, you'll want sum(!complete.cases(DF)), or, equivalently, sum(apply(DF, 1, anyNA))
There are a number of different ways to look at the number, proportion or position of NA values in a data frame:
Most of these start with the logical data frame with TRUE for every NA, and FALSE everywhere else. For the base dataset airquality
is.na(airquality)
There are 44 NA values in this data set
sum(is.na(airquality))
# [1] 44
You can look at the total number of NA values per row or column:
head(rowSums(is.na(airquality)))
# [1] 0 0 0 0 2 1
colSums(is.na(airquality))
# Ozone Solar.R Wind Temp Month Day
37 7 0 0 0 0
You can use anyNA() in place of is.na() as well:
# by row
head(apply(airquality, 1, anyNA))
# [1] FALSE FALSE FALSE FALSE TRUE TRUE
sum(apply(airquality, 1, anyNA))
# [1] 42
# by column
head(apply(airquality, 2, anyNA))
# Ozone Solar.R Wind Temp Month Day
# TRUE TRUE FALSE FALSE FALSE FALSE
sum(apply(airquality, 2, anyNA))
# [1] 2
complete.cases() can be used, but only row-wise:
sum(!complete.cases(airquality))
# [1] 42
回答2:
From the example here:
DF <- read.table(text=" col1 col2 col3
1 23 17 NA
2 55 NA NA
3 24 12 13
4 34 23 12", header=TRUE)
You can check which rows have at least one NA:
(which_nas <- apply(DF, 1, function(X) any(is.na(X))))
# 1 2 3 4
# TRUE TRUE FALSE FALSE
And then count them, identify them or get the ratio:
## Identify them
which(which_nas)
# 1 2
# 1 2
## Count them
length(which(which_nas))
#[1] 2
## Ratio
length(which(which_nas))/nrow(DF)
#[1] 0.5
来源：https://stackoverflow.com/questions/50919161/how-to-simply-count-number-of-rows-with-nas-r